1. Chapter 9 Notes I Stoichiometry

2. Stoichiometry Calculations of quantities in chemical reactions This means using balanced equations to calculate quantities of chemicals used in a chemical reaction

3. A chemical equation is like a recipe; it shows you how much of each “ingredient” is used and how much product you will have in the end.

4. N 2 + 3H 2  2NH 3 How many molecules of N 2 are there? How many molecules of H 2 are there? How many molecules of NH 3 are there? So one molecule of N 2 will react with 3 molecules of H 2 to form 2 molecules of NH 3. You could also say that one mole of N 2 will react with 3 moles of H 2 to form 2 moles of NH 3.

5. The heart of stoichiometry is using a balanced chemical equation as a conversion factor for dimensional analysis.

6. Zn + HCl  ZnCl 2 + H 2 For the above reaction, how many moles of zinc chloride can be produced with 0.27 moles of zinc?

7. Zn +2 HCl  ZnCl 2 + H 2 For the above reaction, how many moles of zinc will react with 1.39 moles of hydrochloric acid?

8. As an experiment... What is the ratio of the reaction of adding sodium to water, producing sodium hydroxide and hydrogen gas? Na + H 2 O  NaOH + H 2

9. So if we started with 0.15 moles of sodium metal, how many moles of hydrogen gas was produced? 2Na +2 H 2 O  2NaOH + H 2

10. Why are mole/mole problems impractical in a laboratory setting?

11. 4Fe + 3O 2  2Fe 2 O 3 How many grams of iron (III) oxide can be produced with 17.2g Fe?

12. 4Fe + 3O 2  2Fe 2 O 3 How many grams of iron will react with 5.25 liters of O 2 (@STP)?

13. 4Fe + 3O 2  2Fe 2 O 3 How many molecules of O 2 are needed to produce 3.92g Fe 2 O 3 ?

14. Density Remember, a conversion from liters to moles is only valid for gases at STP. Converting from/to liters (or mL) for liquids or solids involve using density as a conversion factor.

15. If you have 10.0mL of isopropyl alcohol (C 3 H 7 OH) and burn it, how many liters CO 2 gas are produced @STP? The reaction is combustion. D = 0.798g/mL

16. 10.0mL (C 3 H 7 OH) D = 0.798g/Ml how many liters CO 2 Find Mass using D=M/V

17. Write the reaction 2C 3 H 7 OH + 9O 2  6CO 2 + 8H 2 0 7.98g ? L